1. Field of the Invention
The present invention relates to the control of an emergency exit and more particularly, to a release control mechanism for emergency exit, which can easily be operated with less effort to open the emergency exit in case of an emergency.
2. Description of the Related Art
A conventional emergency exit uses a vertical or horizontal type rolling door to close/open the entrance. Normally, the rolling door of an emergency exit is closed, working as a security door. The rolling door of an emergency exit can be opened through an electric operation mode as well as by a manual operation mode. The rolling door of an emergency exit must be designed to be easily opened in case of an emergency, for example, a fire. According to conventional designs, a torsion spring is provided and coupled to the rolling shaft of the rolling door for automatically rolling up the door panel elements of the rolling door. When a person operated a release control lever to release the torsion spring, the torsion spring immediately bias the rolling shaft of the rolling door, causing the rolling shaft to roll up the door panel elements of the rolling door.
FIGS. 1a and 1b show the operation status of the manual operation mode of an emergency exit according to the prior art. As illustrated, a releasing mechanism (100) is provided having a brake adapted to brake the rolling door in the close position, a release lever (101) adapted to release the brake, a releasing cable (102), which has one end connected to the release lever (101) and the other end connected to a driving mechanism (103), which is controlled to move the releasing cable (102) by an operating rod (104). When turning the operating rod (104) upwards or downwards, the driving mechanism (103) is forced to move the releasing cable (102) and to further drive the release lever (101) to release the brake, enabling the torsion spring to bias the rolling shaft of the rolling door and to further open the emergency exit. Because the driving mechanism (103) is operated through a lever function, the arm of force must be extended so that the driving mechanism (103) can be operated with less effort. During an emergency case, a person trying to escape through the emergency case may have to spend a lot of time in finding the way to operate the driving mechanism (103). Further, it is difficult to an old or handicapped person to operate the operating rod (104).